1. Field of the Invention
The present invention generally relates to information storage apparatuses and information storage methods, and, more particularly, to an information storage apparatus that performs recording by applying a magnetic field to a recording medium.
2. Description of the Related Art
In recent years, there has been a demand for effective power saving techniques in the field of information processing. Particularly, in a magneto-optical disk apparatus, a laser beam and a magnetic field need to be produced for recording and/or reproducing information, and a relatively large power is required.
Meanwhile, in a case where a magneto-optical disk apparatus is mounted on a mobile personal computer or the like, a battery may be employed as a power source. In such a case, the battery wears out when a large amount of power is consumed, resulting in a short driving time. Therefore, it is desirable to reduce the power consumption.
To perform a data write operation in a magneto-optical disk apparatus, an erasing process, a writing process, and a verifying process are performed in that order. In the erasing process, the data in a range in which data is to be written is erased. In the writing process, the data is written in the erase range. In the verifying process, the written data is read out to determine whether or not the writing has been correctly performed.
In the erasing process and the writing process, a magnetic field is applied to the magneto-optical disk, but also a laser beam is emitted onto the magneto-optical disk. In regard to the positional relationship of the magnetic field to be applied, the magneto-optical disk should be adjusted so that the laser beam and the magnetic field are at right angles to the magneto-optical disk. In practical use, however, the magneto-optical disk is chucked with a tilt due to mechanical tolerance, or the mounted lens might be tilted. Consequently, it is very difficult to maintain an ideal positional relationship. The magnetic field is thus set to a large value so that the data write operation can positively be performed even if the relative positional relationships among the laser beam, the magneto-optical disk, and the magnetic field falls under a worst case.
However, with such a large magnetic field, there is a problem that the power consumption becomes large.
A general object of the present invention is to provide information storage apparatuses and methods in which the above problems are eliminated.
A more specific object of the present invention is to provide an information storage apparatus that can reduce power consumption, and a method of recording information with a small amount of power consumption.
According to the present invention, when information is recorded by applying a magnetic field to a recording medium, a control value for controlling the magnitude of the magnetic field generated by a magnetic field generating unit is set within a control range of a predetermined magnetic field. The initial value of the control value is pre-stored, and the initial value is updated to a new control value within the control range depending on error conditions.
With such an information recording apparatus, it is not necessary to set a bias magnetic field for each process to a maximum value, which takes into consideration the tolerance. A default value of the magnetic field may be set, if necessary, so as to minimize the default value and the control range of the magnetic field, depending on the relative relationship of a light beam, the recording medium, and the magnetic field.